Electromechanical analysis of single-walled carbon nanotubes suspended across carbon nanofiber templates using scanning electron microscopy

A real-time and non-contact method using scanning electron microscopy is demonstrated for the electromechanical analysis of suspended single-walled carbon nanotubes (su-SWCNTs) to estimate the adhesive force to the supporting templates. The su-SWCNTs were directly synthesized across vertically-aligned carbon nanofibers (CNFs) with size-reduced catalytic nanoparticles encapsulated at the tips using a special three-step process. Results from the measurements and an analysis by a simplified model, valid for a large deflection regime, reveal a strong non-van der Waals force interaction at the interface. The strong adhesive force observed can be attributed to strong chemical bonds at the SWCNT-CNF junctions and amorphous carbon layers clamping around the tips of the CNFs, both formed during the high temperature catalytic chemical vapor deposition process for SWCNT synthesis. The strong adhesion between the SWCNTs and the supporting templates is highly desirable for the fabrication of reliable SWCNT-based electromechanical devices.